NF1 and gastrointestinal stromal tumor: Nevertheless, the frequent multiplicity of GI tumors constitutes a problem peculiar to GIST-syndromes deserving a special attention, commonly causing acute complications such as hemorrage and, especially in germline KIT/PDGFRA mutations and NF1 (where the small bowel can be involved), occlusion/perforation which can be life-threatening [13, 43, 48].